Spatial and Temporal Covariability Patterns in Chinook Salmon Early Ocean Survival and Oceanic Conditions

We used the coded-wire tag data set to investigate spatial and temporal patterns of covariability in the survival of hatchery reared chinook salmon (Oncorhynchus tshawytscha) from central California to Southeastern Alaska from 1980 to 2006. The spatial and temporal coverage of these data allow analyses that 1) improve our understanding of covariability in early ocean survival across spatial and temporal scales and 2) provide insight into likely scales of physical forcing mechanisms underlying observed spatial and temporal patterns. We found evidence of covariability in survival across life history types for fish released from coastal Washington, the Columbia River, Oregon and California, with increased covariability at finer spatial scales. Spatial correlation scales (50% correlation distance and e^-1 (32.8%) folding distance) were similar to those reported for coho, pink, chum and sockeye salmon, but smaller than those reported for coastal ocean sea-surface temperature and upwelling indices. In addition, there was no support for the idea that chinook salmon originating from southeast Alaska covary inversely with those originating from the California Current System.